Lactarius deliciosus, L.) Gray (group

Barge, Edward G. & Cripps, Cathy L., 2016, New reports, phylogenetic analysis, and a key to Lactarius Pers. in the Greater Yellowstone Ecosystem informed by molecular data, MycoKeys 15, pp. 1-58 : 38-41

Taxon classification Fungi Russulales Russulaceae

20. " Lactarius deliciosus " (L.) Gray (group) Figure 22

Description.

Pileus 30-100 mm in diameter, convex to broadly infundibuliform, smooth to faintly areolate, viscid to dry, ± faintly zonate, pale cream to pale yellow to carrot orange, often with green stains especially in age; margin striate when wet, incurved when young and becoming straight. Lamellae adnate to subdecurrent, crowded to subdistant, creamy orange to carrot orange, discoloring orange to reddish and eventally green where damaged. Stipe 30-70 × 5-25 mm, equal to clavate to tapering toward the base, viscid to dry, smooth, creamy orange to carrot orange with a white band toward the apex; discoloring carrot orange to dull reddish and eventually green where damaged, hollow. Context yellowish, immediately staining carrot orange to dull reddish and eventally green. Latex scarce, carrot orange, staining tissue carrot orange to dull reddish and eventually green. Odor mild. Taste mild.

Basidiospores 7.5-10.5 × 5.5-7.5 µm, Q = 1.3-1.5, ellipsoid; ornamentation forming a partial reticulum. Pleuromacrocystidia 40-55 × 3-6 µm, very sparse, subfusiform; apex moniliform. Cheilomacrocystidia 45-60 × 4-9 µm, scarce to numerous, subfusiform; apex moniliform.

Ecology and distribution.

In North America with conifers. In the GYE, members of this group occur in montane mixed lodgepole/spruce-fir forests, the spruce-fir zone, and the krummholz zone, summer to fall; there are also reports specifically with Pinus flexilis ( Cripps and Antibus 2011) and Pinus albicaulis ( Mohatt et al. 2008, Cripps and Antibus 2011), and one collection is reported here with Arctostaphylos uva-ursi , well-separated from any conifers.

Specimens examined.

U.S.A. MONTANA: Carbon County, Hellroaring Plateau, Hellroaring Creek, among Arctostaphylos uva-ursi , 9 Aug 2015, EB107-15 ( MONT); Gallatin County, Gallatin Range, East Fork Hyalite Creek, under Picea engelmannii , 24 Aug 2014, EB0063-14 ( MONT); Madison County, Madison Range, Taylor Creek, under Abies lasiocarpa , Picea engelmannii and Pinus contorta , 25 July 2015, EB089-15 ( MONT).

Discussion.

While section Deliciosi (Fr.:Fr.) Redeuilh, Verbeken & Walleyn has been resolved as monophyletic ( Nuytinck et al. 2007) (Figure 2B), the complex of species surrounding Lactarius deliciosus (L.) Gray in North America is poorly resolved. Using molecular techniques, Nuytinck et al. (2007) showed that Lactarius deliciosus and Lactarius deterrimus Gröger likely do not occur in North America. The collections of the North American varieties of Lactarius deliciosus described by Hesler and Smith (1979) that they analyzed formed a clade separate from the European Lactarius deliciosus and Lactarius deterrimus , but were poorly resolved, with the exception of Lactarius deliciosus v. areolatus A.H. Smith, which formed a monophyletic group. For descriptions of North American members of this group see Hesler and Smith (1979) and Methven (1997).

Lactarius deliciosus and all of its North American varieties, as well as Lactarius deterrimus have been previously reported from the GYE ( McKnight 1982, Mohatt et al. 2008, Cripps 2011, Cripps and Antibus 2011). Specimens from the GYE included in the phylogenetic analysis in the present study fall in the poorly resolved North American " Lactarius deliciosus " group including " Lactarius deliciosus v. deterrimus " ( Gröger) Hesler & A.H. Sm. and Lactarius deliciosus v. olivaceosordidus Hesler & A.H. Sm. (Figure 2B). Previous reports of Lactarius thyinos from the GYE ( McKnight 1982), a northeastern North American member of sect. Deliciosi that occurs in Thuja bogs may refer to the " Lactarius deliciosus " group described here. Overall, this group is in need of revision.